[danpalmer]

I'm generally in favour of OSes encouraging signed executables from known developers with basic oversight by default. Apple do this, I can and do bypass it, but many don't need to. It's not a huge burden for the sort of software most people tend to run.

But that's not what this is.

By saying "oh by the way go and get our browser instead" it's clear that Microsoft aren't just checking known signing keys, they are directly targeting Firefox and using that knowledge to present high-intent users with an alternative.

It betrays their real intentions, and that's something lawyers love.